1. Field of the Invention
The present invention relates to a resin-sealed piezoelectric oscillator having leads or terminals.
2. Description of the Related Art
No conventional semiconductor devices having a flat package style also contain a piezoelectric oscillator element. FIG. 5A is a plan view showing, as an example of a flat package, a semiconductor device of QFJ (Quad Flat J-Lead Package) type. FIG. 5B is a side view of the semiconductor device of FIG. 5A. An IC chip 52 is mounted on an island portion 51 located approximately in the center of the package. Bonding wires 54 connect the pads of the IC chip 52 to the lead terminals 53 which surround the island portion 51 on its four sides. The entire structure (known as a lead frame) is then sealed with resin using transfer molding, except the outer portion of the lead terminals 53 which are left exposed. The lead terminals 53 are then subjected to cutting and bending processes.
Conventional flat package semiconductor devices (also known as plastic leaded chip carriers) cannot accommodate a piezoelectric oscillator element because the lead terminals 53 surround the island portion 51 and because the resin packages of such conventional devices are too thin.